PSI - Issue 28

M.Z. Sadeghi et al. / Procedia Structural Integrity 28 (2020) 1601–1620 M.Z. Sadeghi et al./ Structural Integrity Procedia 00 (2019) 000–000

1610

a � � 6 1 p � q � 2p � q

where,

q � ���10�p � � 12�3 � 4p � � � 2�p � � p � p � �� p � � � � � �� � � � 10 3 G B b L h

(20)

then by implementing E eq and a e in the following equations, total fracture energy for mixed-mode loading can be calculated. G � G � � G �� (21) G � 12P � E �� b � h � a �� h � � 1 � 5 � � � ��a � � 0�42�� � P � 16b � h � E �� (22) 3. Finite element analysis The numerical evaluation aimed at validation of the experimental data to predict P m was carried out using the cohesive zone model (CZM) formulation available in commercial FEM package Abaqus.The dimensions of SLJ considered in the FEM model is as shown in Fig. 8 and Fig. 9 for a bondline thickness t a = 0.20 mm and 0.90 mm.

Fig. 8. Geometry of the SLJ- (dimensions in mm, width=25 mm).

SLJ modelling based on 2D formulation over the 3D formulation was considered for the computational efficiency involved in this parametric study of different thickness. The variation in with experimentally determined was less than 10%. SLJ was modelled with 2-D plane strain (CPE4) elements. The assumption of plane strain is valid since the adhesive thickness is much smaller in comparison to the thickness of adherents, the deformation in the out of plane direction can be considered negligible (Ajdani et al., 2020). This was validated based on our previous study (Sadeghi et al., 2020) as well. A triangular CZM formulation was used owing to its simplicity and non-linear geometry effects were considered using the nlgeom option in Abaqus. A fine mesh size of 0.05 mm was considered to effectively capture the stress gradients along the bondline and a coarse mesh size of 0.50 mm was considered towards the grip.